Recently, I’ve been trying to update a lot of Orthoptera (grasshoppers/crickets) taxonomy by adding all new species described in 2021, according to Orthoptera Species Files (OSF). It is not uncommon to see OSF use the term “species groups” to apply to subdivisions between genus and species. Why the researchers don’t just describe subgenera, I don’t understand but for the most part, I’ve been handling these “species groups” by creating complexes. And I think if warranted, has significantly helped iNat to include these groups. A good example of which being the genus Melanoplus in which only males can be used for species’ ids but females can be identified to group, and with the addition of complexes to represent species groups, can put a lot of genus level ids down a little finer.
Anyway, to the matter at hand. Prior to today, iNat only had two species under the genus Mecopoda. There is one species group and 8 species linked directly to genus. Should be easy to add a single complex, but the species group according to OSF is further divided into 3 species subgroups, with two species linked directly to species group (see image). All I can say is ugh and I’m not really sure how to handle it.
I think it depends on whether you think there will be a lot of demand for species groups/subgroups. If nobody will be IDing them at that level, very little is lost by just putting them all in the genus, and leaving it at that.
If you think the (sub)groups are useful, then I would put them in. Either (A) just the main (admittedly large) species group with all 18 species directly below it, or (B) just the subgroups with the non-subgrouped taxa linked to the genus. “A” sounds like it would be more consistent with how complexes are currently being used in Orthoptera. “B” seems closer to the typical/intended use of the Complex rank. IMO, do whichever you think will cause the least confusion.
We had a similar issue with the large Hoverfly genus Platycheirus (circa 200 species). In this there are taxonomically recognised subgenera, which in turn are divided into well known species groups - but there are also smaller groups that are widely used and fall within these larger groups. We used the rank ‘Section’ to represent Species Group and Complex for the subgroups. Which is a bit of a fudge, but it at least makes (almost) all the well used divisions available. You can see the discussion here Flag for Taxon: Section Platycheirus albimanus · iNaturalist
One thing to add though, the guidelines do suggest not adding additional taxonomic nodes unless they are genuinely going to be useful, not just because you can.
Also have a look at the rankings here - there is no current way for iNat to deal with Genus Groups which is very annoying for all us Phaneropterinae identifiers :/
Personally, I would give the Species group as the ID, and then add a note explaining that you recognize the sub-groups, with links to your sources. If you are not sure, others possibly can make the distinction.
create the three complexes.
and just leave the two other species under the genus.
Why is this ugh? That is a perfectly acceptable solution.
What would not be acceptable is to create two monospecific complexes, purely to have only a single rank below the genus [unless those have been described as groups in the literature].
Presumably if females of paucidens and stridulata cannot be told apart, they would be identifiable only to genus? So creating a complex for this situation is not pragmatic.